diff --git a/scripts/xsl/indicatorsObservations.xsl b/scripts/xsl/indicatorsObservations.xsl
index 78b2498..81e54aa 100644
--- a/scripts/xsl/indicatorsObservations.xsl
+++ b/scripts/xsl/indicatorsObservations.xsl
@@ -58,7 +58,7 @@
                         and $wbld_date != '2005-2010'
                         and $wbld_country != ''
                         and not(contains($id, ' '))
-                        and not(contains($wbld_date, 'period '))
+                        and not(contains(lower-case($wbld_date), 'period '))
                         ">
 
                 <rdf:Description rdf:about="{$wbld}dataset/world-bank-indicators/{$wbld_indicator}/{$wbld_country}/{wbldfn:get-date($wbld_date)}">